In a comment under this question Jon Ericson suggested a case could be made for "reason" to include "logic" but not vice-versa. I had always had a not-thought-out impression that that is so. Reason might perhaps include the formation of concepts and some norms by which one decides which new concepts are worthwhile. Logic, on the other hand, might only tell us that our definitions of new concepts must not be circular or ambiguous, etc.

I don't think either one of them is broader, they are in different catgories. The use of "reason" in philosophy is more or less in line with the dictionary's "the power of the mind to think, understand, and form judgments by a process of logic", i.e. it is the faculty responsible for implementing (or generating) "logic". The "logic" does not have to be confined to formality (as in mathematical logic) or triviality (as in Aristotelian logic), Hegel's or Husserl's view of it was very expansive, namely all that implemented/generated by reason.
– ConifoldMay 17 '16 at 20:41

@Conifold what about the fact that different logics would together fall under the general heading of reason?
– Alexander S KingMay 17 '16 at 20:50

@Alexander "Different logics" probably uses "logic" in the narrow sense, like classical, paraconsistent, personal 'logic', etc., and "falling under" is probably a shorthand, as in "shapes and colors fall under vision, and sounds under hearing".
– ConifoldMay 17 '16 at 21:34

I've slightly modified your first sentence (actually, the modification is unnecessary because the scope of this SE is philosophy but it does make it clearer).
– virmaiorMay 17 '16 at 23:11

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@MichaelHardy can you clarify further the context where you're asking about the use of "reason" vs. "logic"? It may be impossible to give a sufficient answer without that.
– virmaiorMay 18 '16 at 1:25

3 Answers
3

While I certainly defer to Virmaior's excellent answer and its interesting tail of commentary, can this be anything but a question of terminology, probably settled only in ancient Greek etymology?

The term "broader" creates problems. In ordinary language people "give reasons," as Rorty liked to put it. Anyone and everyone goes through life answering "because" questions, and it takes no special training and, mostly crucially, no definitive or numerical exclusions. To "give reasons" can be ambiguous and ironic, it allows parable and paradox. In this existential and sociological sense it can be seen as "broader." Available to all.

On the other hand, "logos" is the suffix affixed to all fields of knowledge, presumably to get at the universal essence of things. Whether such universality is "broader" than human beings "reasoning" with one another is, of course, one of the great, abiding disputes of philosophy. Husserl, perhaps, is a paradigmatic modern case of the idea that some sort of necessary "logic" is inclusive of what can be properly "reasoned."

My own sense is that most people (aka "me") would consider "reasoning" broader. And the reason is that is can include compelling forces of irony, paradox, parable, double meanings, etc. in a way that "logic" must rule out. And it would be wrong to conclude that "logic" is thereby more precise, necessary, and universal. As the various forms of "indeterminacy" that have become embedded in modern physics indicate, it is logic that must answer to reason.

Logic struggles to be precise. For the human capacity to "reason" absolute precision is not only infinitely regressive, it is death, closure.

From an etymological view, logic is broader than reason; logic is a strand of words called a sentence; this sentence expresses an idea (logic) or multiple ideas (logics) simultaneously; the idea or ideas are judged to be whole, a degree of rationality is diagnosed to determine the complexity of a sentence.

To reason is to dissects the whole into parts, to dissect a sentence into parts, identify the meaning of each part of the sentence to understand the idea the sentence conveys; the idea conveyed is one of the definitions of logic. Logic studies the process of rationing the whole to understandable parts to have clear, coherent ideas, or reasoned arguments. a synthesized production of ideas communicated into one general idea or multiple ideas with similarity or congrency of thought is studied by logic as well. Logic studies the ability to articulate analyzed, synthesized, evaluative and creative ideas that have soundness and originality, or newness and freshness.

One could say logic is narrower; reason could be the umbrella, and logic is the subfield to reason; multiple fields in logic exist; logic is the expressed dissected parts of the whole rather than reason dissecting logic into parts to understand and define logic.
If reason is broader than logic, it sounds like reason studies logic; this view is called metalogic. Reason dissects logic to understand 'logical' statements which explains why there are many schools of thought in logic.

Etymologically, this is a weird point of view. Logos, properly speaking, has very little to do with sentences and ratio (which lies at the basis of our word "reason") was a frequent translation of logos in a philosophical (not theological) context hence, for example, the (famous) rendering of Aristotle's zoon logoi echon as animal rationale.
– ig0774May 17 '16 at 21:29

There must be multiple usages of the word 'reason' and 'logic'; I wrote this statement based on etymonline.com understanding.
– SergeyMay 17 '16 at 21:41

Indeed, there are multiple uses... My impression is the question is unanswerable without some further specification.
– ig0774May 17 '16 at 21:42

I know that logic means three different things: reason, idea, word. I see logic as the study of ideas expressed in symbolic terms that convey sound and sophisticated thinking; this is likely what we call reason. Reasoning puts words together to convey ideas. It's possible I see logic as the process of putting words together to communicate sophisticated ideas to articulate a clear point of view; strangely, this definition doesn't require accuracy or accuracy is a product of reasoned out, meaning thoughtfully constructed ideas.
– SergeyMay 17 '16 at 22:05

If logic studies reason how can it be "broader" than reason? It is like saying that anthropology is broader than the human race which it studies???
– ConifoldMay 17 '16 at 22:27

Within contemporary philosophy, "logic" is narrower than "reason." We can waste our time in etymology, but the key is how the terms are used in the discipline.

In most* contemporary philosophy, "logic" refers to sentential logic, truth-predicate logic, modal logic, deontic logic, and other variations on the formalization and evaluation of arguments in this way. The adjectival use "logical" has a broader meaning that encompasses things authors think are close that level of rigor. (See for instance The Journal of Philosophical Logic).

I qualified the above paragraph with a most. Allow me to explain. There's a supposed divide between "continental" and "analytic" philosophy (here I will sketch it briefly just to relate it to the point). It's much touted by some who write about philosophy (rather than philosopher per se), and it's beloved by two groups within philosophy. First, it's beloved by a group of self-styled "continental" philosophers who use "analytic" pejoratively to refer to people doing the sort of metaphysics that grew out of logical positivism, philosophy of language, formal logic, etc. Second, there's a mirror group of "analytic" philosophers who use the term "continental" philosophy to refer to word salads and grandiose claims made by people who do philosophy with less "rigor." For the most part, this distinction does not make too much sense. We can draw some fuzzier lines by pointing out that most Frege, Carnap, and Russell scholars are going to be in the anti-"continental" camp and that many Derrida, Hegel, Levinas, Foucault scholars are going to be in the anti-"analytic" camp. But this is far from an absolute test... This long digression to say that among the "continental" hard liners (as Brian Leiter calls them), here are some people who will use "logic" and "reason" in ways that are unlike the breakdown suggested in the answer. (As a counterexample, Kenneth Westphal uses the terms in the "standard way" and is a Hegel scholar; Brad Stone also publishes using the standard distinction and does Foucault and Heidegger).

"Reason" in contrast is going to be harder to define for contemporary philosophy. Reason is the name of a faculty in modern German philosophy that is above and beyond understanding. Thus, Kant's Critique of Pure Reason is a critique that uses reason to critique the claims of the understanding and seeks to delimit the function of understanding (and to a lesser extent the function of reason). For Hegel, Reason is the more important faculty.

In a separate stream, reason is used in a manner pretty close to any dictionary usage to refer to our capacity to think. This, often, is too imprecise so the generic capacity is sometimes called "ratiocination" (in part because that word is so obscure that no one brings pre-conceptions to the table with).

Reason is also an important concept in medieval philosophy from which the modern German philosophy inherits and develops the concept. For the medievals, logic is a propaedeutic to the study of philosophy (i.e. reasoning) which precedes the ability to do good theology.

In ancient philosophy, things are really confusing on this front because as ig0774 points out in a comment the Latin word ratio is the most common translation of logos with philosophy. So thinking about the neo-Platonists, there's not really a difference except when one is manufactured to make a point there...

While your description may cover dominant uses of "logic" by analytic philosophers, I do not think continental ones would endorse it. See D’Agostini on "the role of logic in the analytic continental divide", and the "dominance of Hegel’s concept of logic (and theory of concept) in twentieth-century continental philosophy" tandfonline.com/doi/pdf/10.1080/09672550110058821 .
– ConifoldMay 18 '16 at 0:00

That's really going to greatly depend on how you define "continental ones." Sure, Zizek and Heidegger themselves aren't going to use the terms this way (pro tip: don't try to write the way they do). Conversely, I'm generally considered a continental philosopher based on my publication record, and this is most definitely how I would use the terms. Even if I was writing on Hegel's logic, I would need to say Encyclopedia Logic or longer logic for even most Hegel scholars to know what I'm talking about. So it's kind of weird having it suggested to me continental guys don't write this way ...
– virmaiorMay 18 '16 at 0:40

But I'll make a few amendments to the answer to address your point.
– virmaiorMay 18 '16 at 0:41

I remember Heidegger's "degeneration of logic into logistic" that was at the origin of the divide. But Deleuze's Logic of Sense is also quite Hegelian. Husserl detested Hegel and is a mediating figure, but someone encountering Logical Investigations might wonder why it is so called, or what he and Kant meant by "transcendental logic". The question does not collapse philosophy into narrow modernity, and history is more than etymology. So used-in-academic-departments-today can't be the only key.
– ConifoldMay 18 '16 at 1:17

Okay fair enough. I've joined you in requesting clarification from the OP.
– virmaiorMay 18 '16 at 1:49